1// unique_ptr implementation -*- C++ -*-
2
3// Copyright (C) 2008-2025 Free Software Foundation, Inc.
4//
5// This file is part of the GNU ISO C++ Library. This library is free
6// software; you can redistribute it and/or modify it under the
7// terms of the GNU General Public License as published by the
8// Free Software Foundation; either version 3, or (at your option)
9// any later version.
10
11// This library is distributed in the hope that it will be useful,
12// but WITHOUT ANY WARRANTY; without even the implied warranty of
13// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14// GNU General Public License for more details.
15
16// Under Section 7 of GPL version 3, you are granted additional
17// permissions described in the GCC Runtime Library Exception, version
18// 3.1, as published by the Free Software Foundation.
19
20// You should have received a copy of the GNU General Public License and
21// a copy of the GCC Runtime Library Exception along with this program;
22// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23// <http://www.gnu.org/licenses/>.
24
25/** @file bits/unique_ptr.h
26 * This is an internal header file, included by other library headers.
27 * Do not attempt to use it directly. @headername{memory}
28 */
29
30#ifndef _UNIQUE_PTR_H
31#define _UNIQUE_PTR_H 1
32
33#include <bits/c++config.h>
34#include <debug/assertions.h>
35#include <type_traits>
36#include <tuple>
37#include <bits/stl_function.h>
38#include <bits/functional_hash.h>
39#if __cplusplus >= 202002L
40# include <compare>
41# if _GLIBCXX_HOSTED
42# include <bits/ostream.h>
43# endif
44#endif
45
46namespace std _GLIBCXX_VISIBILITY(default)
47{
48_GLIBCXX_BEGIN_NAMESPACE_VERSION
49
50 /**
51 * @addtogroup pointer_abstractions
52 * @{
53 */
54
55#if _GLIBCXX_USE_DEPRECATED
56#pragma GCC diagnostic push
57#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
58 template<typename> class auto_ptr;
59#pragma GCC diagnostic pop
60#endif
61
62 /** Primary template of default_delete, used by unique_ptr for single objects
63 *
64 * @headerfile memory
65 * @since C++11
66 */
67 template<typename _Tp>
68 struct default_delete
69 {
70 /// Default constructor
71 constexpr default_delete() noexcept = default;
72
73 /** @brief Converting constructor.
74 *
75 * Allows conversion from a deleter for objects of another type, `_Up`,
76 * only if `_Up*` is convertible to `_Tp*`.
77 */
78 template<typename _Up,
79 typename = _Require<is_convertible<_Up*, _Tp*>>>
80 _GLIBCXX23_CONSTEXPR
81 default_delete(const default_delete<_Up>&) noexcept { }
82
83 /// Calls `delete __ptr`
84 _GLIBCXX23_CONSTEXPR
85 void
86 operator()(_Tp* __ptr) const
87 {
88 static_assert(!is_void<_Tp>::value,
89 "can't delete pointer to incomplete type");
90 static_assert(sizeof(_Tp)>0,
91 "can't delete pointer to incomplete type");
92 delete __ptr;
93 }
94 };
95
96 // _GLIBCXX_RESOLVE_LIB_DEFECTS
97 // DR 740 - omit specialization for array objects with a compile time length
98
99 /** Specialization of default_delete for arrays, used by `unique_ptr<T[]>`
100 *
101 * @headerfile memory
102 * @since C++11
103 */
104 template<typename _Tp>
105 struct default_delete<_Tp[]>
106 {
107 public:
108 /// Default constructor
109 constexpr default_delete() noexcept = default;
110
111 /** @brief Converting constructor.
112 *
113 * Allows conversion from a deleter for arrays of another type, such as
114 * a const-qualified version of `_Tp`.
115 *
116 * Conversions from types derived from `_Tp` are not allowed because
117 * it is undefined to `delete[]` an array of derived types through a
118 * pointer to the base type.
119 */
120 template<typename _Up,
121 typename = _Require<is_convertible<_Up(*)[], _Tp(*)[]>>>
122 _GLIBCXX23_CONSTEXPR
123 default_delete(const default_delete<_Up[]>&) noexcept { }
124
125 /// Calls `delete[] __ptr`
126 template<typename _Up>
127 _GLIBCXX23_CONSTEXPR
128 typename enable_if<is_convertible<_Up(*)[], _Tp(*)[]>::value>::type
129 operator()(_Up* __ptr) const
130 {
131 static_assert(sizeof(_Tp)>0,
132 "can't delete pointer to incomplete type");
133 delete [] __ptr;
134 }
135 };
136
137 /// @cond undocumented
138
139 // Manages the pointer and deleter of a unique_ptr
140 template <typename _Tp, typename _Dp>
141 class __uniq_ptr_impl
142 {
143 template <typename _Up, typename _Ep, typename = void>
144 struct _Ptr
145 {
146 using type = _Up*;
147 };
148
149 template <typename _Up, typename _Ep>
150 struct
151 _Ptr<_Up, _Ep, __void_t<typename remove_reference<_Ep>::type::pointer>>
152 {
153 using type = typename remove_reference<_Ep>::type::pointer;
154 };
155
156 public:
157 using _DeleterConstraint = enable_if<
158 __and_<__not_<is_pointer<_Dp>>,
159 is_default_constructible<_Dp>>::value>;
160
161 using pointer = typename _Ptr<_Tp, _Dp>::type;
162
163 static_assert( !is_rvalue_reference<_Dp>::value,
164 "unique_ptr's deleter type must be a function object type"
165 " or an lvalue reference type" );
166
167 __uniq_ptr_impl() = default;
168 _GLIBCXX23_CONSTEXPR
169 __uniq_ptr_impl(pointer __p) : _M_t() { _M_ptr() = __p; }
170
171 template<typename _Del>
172 _GLIBCXX23_CONSTEXPR
173 __uniq_ptr_impl(pointer __p, _Del&& __d)
174 : _M_t(__p, std::forward<_Del>(__d)) { }
175
176 _GLIBCXX23_CONSTEXPR
177 __uniq_ptr_impl(__uniq_ptr_impl&& __u) noexcept
178 : _M_t(std::move(__u._M_t))
179 { __u._M_ptr() = nullptr; }
180
181 _GLIBCXX23_CONSTEXPR
182 __uniq_ptr_impl& operator=(__uniq_ptr_impl&& __u) noexcept
183 {
184 reset(p: __u.release());
185 _M_deleter() = std::forward<_Dp>(__u._M_deleter());
186 return *this;
187 }
188
189 _GLIBCXX23_CONSTEXPR
190 pointer& _M_ptr() noexcept { return std::get<0>(_M_t); }
191 _GLIBCXX23_CONSTEXPR
192 pointer _M_ptr() const noexcept { return std::get<0>(_M_t); }
193 _GLIBCXX23_CONSTEXPR
194 _Dp& _M_deleter() noexcept { return std::get<1>(_M_t); }
195 _GLIBCXX23_CONSTEXPR
196 const _Dp& _M_deleter() const noexcept { return std::get<1>(_M_t); }
197
198 _GLIBCXX23_CONSTEXPR
199 void reset(pointer __p) noexcept
200 {
201 const pointer __old_p = _M_ptr();
202 _M_ptr() = __p;
203 if (__old_p)
204 _M_deleter()(__old_p);
205 }
206
207 _GLIBCXX23_CONSTEXPR
208 pointer release() noexcept
209 {
210 pointer __p = _M_ptr();
211 _M_ptr() = nullptr;
212 return __p;
213 }
214
215 _GLIBCXX23_CONSTEXPR
216 void
217 swap(__uniq_ptr_impl& __rhs) noexcept
218 {
219 using std::swap;
220 swap(this->_M_ptr(), __rhs._M_ptr());
221 swap(this->_M_deleter(), __rhs._M_deleter());
222 }
223
224 private:
225 tuple<pointer, _Dp> _M_t;
226 };
227
228 // Defines move construction + assignment as either defaulted or deleted.
229 template <typename _Tp, typename _Dp,
230 bool = is_move_constructible<_Dp>::value,
231 bool = is_move_assignable<_Dp>::value>
232 struct __uniq_ptr_data : __uniq_ptr_impl<_Tp, _Dp>
233 {
234 using __uniq_ptr_impl<_Tp, _Dp>::__uniq_ptr_impl;
235 __uniq_ptr_data(__uniq_ptr_data&&) = default;
236 __uniq_ptr_data& operator=(__uniq_ptr_data&&) = default;
237 };
238
239 template <typename _Tp, typename _Dp>
240 struct __uniq_ptr_data<_Tp, _Dp, true, false> : __uniq_ptr_impl<_Tp, _Dp>
241 {
242 using __uniq_ptr_impl<_Tp, _Dp>::__uniq_ptr_impl;
243 __uniq_ptr_data(__uniq_ptr_data&&) = default;
244 __uniq_ptr_data& operator=(__uniq_ptr_data&&) = delete;
245 };
246
247 template <typename _Tp, typename _Dp>
248 struct __uniq_ptr_data<_Tp, _Dp, false, true> : __uniq_ptr_impl<_Tp, _Dp>
249 {
250 using __uniq_ptr_impl<_Tp, _Dp>::__uniq_ptr_impl;
251 __uniq_ptr_data(__uniq_ptr_data&&) = delete;
252 __uniq_ptr_data& operator=(__uniq_ptr_data&&) = default;
253 };
254
255 template <typename _Tp, typename _Dp>
256 struct __uniq_ptr_data<_Tp, _Dp, false, false> : __uniq_ptr_impl<_Tp, _Dp>
257 {
258 using __uniq_ptr_impl<_Tp, _Dp>::__uniq_ptr_impl;
259 __uniq_ptr_data(__uniq_ptr_data&&) = delete;
260 __uniq_ptr_data& operator=(__uniq_ptr_data&&) = delete;
261 };
262 /// @endcond
263
264 // 20.7.1.2 unique_ptr for single objects.
265
266 /// A move-only smart pointer that manages unique ownership of a resource.
267 /// @headerfile memory
268 /// @since C++11
269 template <typename _Tp, typename _Dp = default_delete<_Tp>>
270 class unique_ptr
271 {
272 template <typename _Up>
273 using _DeleterConstraint =
274 typename __uniq_ptr_impl<_Tp, _Up>::_DeleterConstraint::type;
275
276 __uniq_ptr_data<_Tp, _Dp> _M_t;
277
278 public:
279 using pointer = typename __uniq_ptr_impl<_Tp, _Dp>::pointer;
280 using element_type = _Tp;
281 using deleter_type = _Dp;
282
283 private:
284 // helper template for detecting a safe conversion from another
285 // unique_ptr
286 template<typename _Up, typename _Ep>
287 using __safe_conversion_up = __and_<
288 is_convertible<typename unique_ptr<_Up, _Ep>::pointer, pointer>,
289 __not_<is_array<_Up>>
290 >;
291
292 public:
293 // Constructors.
294
295 /// Default constructor, creates a unique_ptr that owns nothing.
296 template<typename _Del = _Dp, typename = _DeleterConstraint<_Del>>
297 constexpr unique_ptr() noexcept
298 : _M_t()
299 { }
300
301 /** Takes ownership of a pointer.
302 *
303 * @param __p A pointer to an object of @c element_type
304 *
305 * The deleter will be value-initialized.
306 */
307 template<typename _Del = _Dp, typename = _DeleterConstraint<_Del>>
308 _GLIBCXX23_CONSTEXPR
309 explicit
310 unique_ptr(pointer __p) noexcept
311 : _M_t(__p)
312 { }
313
314 /** Takes ownership of a pointer.
315 *
316 * @param __p A pointer to an object of @c element_type
317 * @param __d A reference to a deleter.
318 *
319 * The deleter will be initialized with @p __d
320 */
321 template<typename _Del = deleter_type,
322 typename = _Require<is_copy_constructible<_Del>>>
323 _GLIBCXX23_CONSTEXPR
324 unique_ptr(pointer __p, const deleter_type& __d) noexcept
325 : _M_t(__p, __d) { }
326
327 /** Takes ownership of a pointer.
328 *
329 * @param __p A pointer to an object of @c element_type
330 * @param __d An rvalue reference to a (non-reference) deleter.
331 *
332 * The deleter will be initialized with @p std::move(__d)
333 */
334 template<typename _Del = deleter_type,
335 typename = _Require<is_move_constructible<_Del>>>
336 _GLIBCXX23_CONSTEXPR
337 unique_ptr(pointer __p,
338 __enable_if_t<!is_lvalue_reference<_Del>::value,
339 _Del&&> __d) noexcept
340 : _M_t(__p, std::move(__d))
341 { }
342
343 template<typename _Del = deleter_type,
344 typename _DelUnref = typename remove_reference<_Del>::type>
345 _GLIBCXX23_CONSTEXPR
346 unique_ptr(pointer,
347 __enable_if_t<is_lvalue_reference<_Del>::value,
348 _DelUnref&&>) = delete;
349
350 /// Creates a unique_ptr that owns nothing.
351 template<typename _Del = _Dp, typename = _DeleterConstraint<_Del>>
352 constexpr unique_ptr(nullptr_t) noexcept
353 : _M_t()
354 { }
355
356 // Move constructors.
357
358 /// Move constructor.
359 unique_ptr(unique_ptr&&) = default;
360
361 /** @brief Converting constructor from another type
362 *
363 * Requires that the pointer owned by @p __u is convertible to the
364 * type of pointer owned by this object, @p __u does not own an array,
365 * and @p __u has a compatible deleter type.
366 */
367 template<typename _Up, typename _Ep, typename = _Require<
368 __safe_conversion_up<_Up, _Ep>,
369 __conditional_t<is_reference<_Dp>::value,
370 is_same<_Ep, _Dp>,
371 is_convertible<_Ep, _Dp>>>>
372 _GLIBCXX23_CONSTEXPR
373 unique_ptr(unique_ptr<_Up, _Ep>&& __u) noexcept
374 : _M_t(__u.release(), std::forward<_Ep>(__u.get_deleter()))
375 { }
376
377#if _GLIBCXX_USE_DEPRECATED
378#pragma GCC diagnostic push
379#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
380 /// Converting constructor from @c auto_ptr
381 template<typename _Up,
382 typename = _Require<is_convertible<_Up*, pointer>,
383 is_same<_Dp, default_delete<_Tp>>>>
384 unique_ptr(auto_ptr<_Up>&& __u) noexcept;
385#pragma GCC diagnostic pop
386#endif
387
388 /// Destructor, invokes the deleter if the stored pointer is not null.
389#if __cplusplus > 202002L && __cpp_constexpr_dynamic_alloc
390 constexpr
391#endif
392 ~unique_ptr() noexcept
393 {
394 static_assert(__is_invocable<deleter_type&, pointer>::value,
395 "unique_ptr's deleter must be invocable with a pointer");
396 auto& __ptr = _M_t._M_ptr();
397 if (__ptr != nullptr)
398 get_deleter()(std::move(__ptr));
399 __ptr = pointer();
400 }
401
402 // Assignment.
403
404 /** @brief Move assignment operator.
405 *
406 * Invokes the deleter if this object owns a pointer.
407 */
408 unique_ptr& operator=(unique_ptr&&) = default;
409
410 /** @brief Assignment from another type.
411 *
412 * @param __u The object to transfer ownership from, which owns a
413 * convertible pointer to a non-array object.
414 *
415 * Invokes the deleter if this object owns a pointer.
416 */
417 template<typename _Up, typename _Ep>
418 _GLIBCXX23_CONSTEXPR
419 typename enable_if< __and_<
420 __safe_conversion_up<_Up, _Ep>,
421 is_assignable<deleter_type&, _Ep&&>
422 >::value,
423 unique_ptr&>::type
424 operator=(unique_ptr<_Up, _Ep>&& __u) noexcept
425 {
426 reset(p: __u.release());
427 get_deleter() = std::forward<_Ep>(__u.get_deleter());
428 return *this;
429 }
430
431 /// Reset the %unique_ptr to empty, invoking the deleter if necessary.
432 _GLIBCXX23_CONSTEXPR
433 unique_ptr&
434 operator=(nullptr_t) noexcept
435 {
436 reset();
437 return *this;
438 }
439
440 // Observers.
441
442 /// Dereference the stored pointer.
443 _GLIBCXX23_CONSTEXPR
444 typename add_lvalue_reference<element_type>::type
445 operator*() const noexcept(noexcept(*std::declval<pointer>()))
446 {
447#if _GLIBCXX_USE_BUILTIN_TRAIT(__reference_converts_from_temporary)
448 // _GLIBCXX_RESOLVE_LIB_DEFECTS
449 // 4148. unique_ptr::operator* should not allow dangling references
450 using _ResT = typename add_lvalue_reference<element_type>::type;
451 using _DerefT = decltype(*get());
452 static_assert(!__reference_converts_from_temporary(_ResT, _DerefT),
453 "operator* must not return a dangling reference");
454#endif
455 __glibcxx_assert(get() != pointer());
456 return *get();
457 }
458
459 /// Return the stored pointer.
460 _GLIBCXX23_CONSTEXPR
461 pointer
462 operator->() const noexcept
463 {
464 _GLIBCXX_DEBUG_PEDASSERT(get() != pointer());
465 return get();
466 }
467
468 /// Return the stored pointer.
469 _GLIBCXX23_CONSTEXPR
470 pointer
471 get() const noexcept
472 { return _M_t._M_ptr(); }
473
474 /// Return a reference to the stored deleter.
475 _GLIBCXX23_CONSTEXPR
476 deleter_type&
477 get_deleter() noexcept
478 { return _M_t._M_deleter(); }
479
480 /// Return a reference to the stored deleter.
481 _GLIBCXX23_CONSTEXPR
482 const deleter_type&
483 get_deleter() const noexcept
484 { return _M_t._M_deleter(); }
485
486 /// Return @c true if the stored pointer is not null.
487 _GLIBCXX23_CONSTEXPR
488 explicit operator bool() const noexcept
489 { return get() == pointer() ? false : true; }
490
491 // Modifiers.
492
493 /// Release ownership of any stored pointer.
494 _GLIBCXX23_CONSTEXPR
495 pointer
496 release() noexcept
497 { return _M_t.release(); }
498
499 /** @brief Replace the stored pointer.
500 *
501 * @param __p The new pointer to store.
502 *
503 * The deleter will be invoked if a pointer is already owned.
504 */
505 _GLIBCXX23_CONSTEXPR
506 void
507 reset(pointer __p = pointer()) noexcept
508 {
509 static_assert(__is_invocable<deleter_type&, pointer>::value,
510 "unique_ptr's deleter must be invocable with a pointer");
511 _M_t.reset(std::move(__p));
512 }
513
514 /// Exchange the pointer and deleter with another object.
515 _GLIBCXX23_CONSTEXPR
516 void
517 swap(unique_ptr& __u) noexcept
518 {
519 static_assert(__is_swappable<_Dp>::value, "deleter must be swappable");
520 _M_t.swap(__u._M_t);
521 }
522
523 // Disable copy from lvalue.
524 unique_ptr(const unique_ptr&) = delete;
525 unique_ptr& operator=(const unique_ptr&) = delete;
526
527 private:
528#ifdef __glibcxx_out_ptr
529 template<typename, typename, typename...>
530 friend class out_ptr_t;
531 template<typename, typename, typename...>
532 friend class inout_ptr_t;
533#endif
534 };
535
536 // 20.7.1.3 unique_ptr for array objects with a runtime length
537 // [unique.ptr.runtime]
538 // _GLIBCXX_RESOLVE_LIB_DEFECTS
539 // DR 740 - omit specialization for array objects with a compile time length
540
541 /// A move-only smart pointer that manages unique ownership of an array.
542 /// @headerfile memory
543 /// @since C++11
544 template<typename _Tp, typename _Dp>
545 class unique_ptr<_Tp[], _Dp>
546 {
547 template <typename _Up>
548 using _DeleterConstraint =
549 typename __uniq_ptr_impl<_Tp, _Up>::_DeleterConstraint::type;
550
551 __uniq_ptr_data<_Tp, _Dp> _M_t;
552
553 // like is_base_of<_Tp, _Up> but false if unqualified types are the same
554 template<typename _Up>
555 using __is_derived_Tp
556 = __and_< is_base_of<_Tp, _Up>,
557 __not_<is_same<__remove_cv_t<_Tp>, __remove_cv_t<_Up>>> >;
558
559 public:
560 using pointer = typename __uniq_ptr_impl<_Tp, _Dp>::pointer;
561 using element_type = _Tp;
562 using deleter_type = _Dp;
563
564 // helper template for detecting a safe conversion from another
565 // unique_ptr
566 template<typename _Up, typename _Ep,
567 typename _UPtr = unique_ptr<_Up, _Ep>,
568 typename _UP_pointer = typename _UPtr::pointer,
569 typename _UP_element_type = typename _UPtr::element_type>
570 using __safe_conversion_up = __and_<
571 is_array<_Up>,
572 is_same<pointer, element_type*>,
573 is_same<_UP_pointer, _UP_element_type*>,
574 is_convertible<_UP_element_type(*)[], element_type(*)[]>
575 >;
576
577 // helper template for detecting a safe conversion from a raw pointer
578 template<typename _Up>
579 using __safe_conversion_raw = __and_<
580 __or_<__or_<is_same<_Up, pointer>,
581 is_same<_Up, nullptr_t>>,
582 __and_<is_pointer<_Up>,
583 is_same<pointer, element_type*>,
584 is_convertible<
585 typename remove_pointer<_Up>::type(*)[],
586 element_type(*)[]>
587 >
588 >
589 >;
590
591 // Constructors.
592
593 /// Default constructor, creates a unique_ptr that owns nothing.
594 template<typename _Del = _Dp, typename = _DeleterConstraint<_Del>>
595 constexpr unique_ptr() noexcept
596 : _M_t()
597 { }
598
599 /** Takes ownership of a pointer.
600 *
601 * @param __p A pointer to an array of a type safely convertible
602 * to an array of @c element_type
603 *
604 * The deleter will be value-initialized.
605 */
606 template<typename _Up,
607 typename _Vp = _Dp,
608 typename = _DeleterConstraint<_Vp>,
609 typename = typename enable_if<
610 __safe_conversion_raw<_Up>::value, bool>::type>
611 _GLIBCXX23_CONSTEXPR
612 explicit
613 unique_ptr(_Up __p) noexcept
614 : _M_t(__p)
615 { }
616
617 /** Takes ownership of a pointer.
618 *
619 * @param __p A pointer to an array of a type safely convertible
620 * to an array of @c element_type
621 * @param __d A reference to a deleter.
622 *
623 * The deleter will be initialized with @p __d
624 */
625 template<typename _Up, typename _Del = deleter_type,
626 typename = _Require<__safe_conversion_raw<_Up>,
627 is_copy_constructible<_Del>>>
628 _GLIBCXX23_CONSTEXPR
629 unique_ptr(_Up __p, const deleter_type& __d) noexcept
630 : _M_t(__p, __d) { }
631
632 /** Takes ownership of a pointer.
633 *
634 * @param __p A pointer to an array of a type safely convertible
635 * to an array of @c element_type
636 * @param __d A reference to a deleter.
637 *
638 * The deleter will be initialized with @p std::move(__d)
639 */
640 template<typename _Up, typename _Del = deleter_type,
641 typename = _Require<__safe_conversion_raw<_Up>,
642 is_move_constructible<_Del>>>
643 _GLIBCXX23_CONSTEXPR
644 unique_ptr(_Up __p,
645 __enable_if_t<!is_lvalue_reference<_Del>::value,
646 _Del&&> __d) noexcept
647 : _M_t(std::move(__p), std::move(__d))
648 { }
649
650 template<typename _Up, typename _Del = deleter_type,
651 typename _DelUnref = typename remove_reference<_Del>::type,
652 typename = _Require<__safe_conversion_raw<_Up>>>
653 unique_ptr(_Up,
654 __enable_if_t<is_lvalue_reference<_Del>::value,
655 _DelUnref&&>) = delete;
656
657 /// Move constructor.
658 unique_ptr(unique_ptr&&) = default;
659
660 /// Creates a unique_ptr that owns nothing.
661 template<typename _Del = _Dp, typename = _DeleterConstraint<_Del>>
662 constexpr unique_ptr(nullptr_t) noexcept
663 : _M_t()
664 { }
665
666 template<typename _Up, typename _Ep, typename = _Require<
667 __safe_conversion_up<_Up, _Ep>,
668 __conditional_t<is_reference<_Dp>::value,
669 is_same<_Ep, _Dp>,
670 is_convertible<_Ep, _Dp>>>>
671 _GLIBCXX23_CONSTEXPR
672 unique_ptr(unique_ptr<_Up, _Ep>&& __u) noexcept
673 : _M_t(__u.release(), std::forward<_Ep>(__u.get_deleter()))
674 { }
675
676 /// Destructor, invokes the deleter if the stored pointer is not null.
677#if __cplusplus > 202002L && __cpp_constexpr_dynamic_alloc
678 constexpr
679#endif
680 ~unique_ptr()
681 {
682 auto& __ptr = _M_t._M_ptr();
683 if (__ptr != nullptr)
684 get_deleter()(__ptr);
685 __ptr = pointer();
686 }
687
688 // Assignment.
689
690 /** @brief Move assignment operator.
691 *
692 * Invokes the deleter if this object owns a pointer.
693 */
694 unique_ptr&
695 operator=(unique_ptr&&) = default;
696
697 /** @brief Assignment from another type.
698 *
699 * @param __u The object to transfer ownership from, which owns a
700 * convertible pointer to an array object.
701 *
702 * Invokes the deleter if this object owns a pointer.
703 */
704 template<typename _Up, typename _Ep>
705 _GLIBCXX23_CONSTEXPR
706 typename
707 enable_if<__and_<__safe_conversion_up<_Up, _Ep>,
708 is_assignable<deleter_type&, _Ep&&>
709 >::value,
710 unique_ptr&>::type
711 operator=(unique_ptr<_Up, _Ep>&& __u) noexcept
712 {
713 reset(__u.release());
714 get_deleter() = std::forward<_Ep>(__u.get_deleter());
715 return *this;
716 }
717
718 /// Reset the %unique_ptr to empty, invoking the deleter if necessary.
719 _GLIBCXX23_CONSTEXPR
720 unique_ptr&
721 operator=(nullptr_t) noexcept
722 {
723 reset();
724 return *this;
725 }
726
727 // Observers.
728
729 /// Access an element of owned array.
730 _GLIBCXX23_CONSTEXPR
731 typename std::add_lvalue_reference<element_type>::type
732 operator[](size_t __i) const
733 {
734 __glibcxx_assert(get() != pointer());
735 return get()[__i];
736 }
737
738 /// Return the stored pointer.
739 _GLIBCXX23_CONSTEXPR
740 pointer
741 get() const noexcept
742 { return _M_t._M_ptr(); }
743
744 /// Return a reference to the stored deleter.
745 _GLIBCXX23_CONSTEXPR
746 deleter_type&
747 get_deleter() noexcept
748 { return _M_t._M_deleter(); }
749
750 /// Return a reference to the stored deleter.
751 _GLIBCXX23_CONSTEXPR
752 const deleter_type&
753 get_deleter() const noexcept
754 { return _M_t._M_deleter(); }
755
756 /// Return @c true if the stored pointer is not null.
757 _GLIBCXX23_CONSTEXPR
758 explicit operator bool() const noexcept
759 { return get() == pointer() ? false : true; }
760
761 // Modifiers.
762
763 /// Release ownership of any stored pointer.
764 _GLIBCXX23_CONSTEXPR
765 pointer
766 release() noexcept
767 { return _M_t.release(); }
768
769 /** @brief Replace the stored pointer.
770 *
771 * @param __p The new pointer to store.
772 *
773 * The deleter will be invoked if a pointer is already owned.
774 */
775 template <typename _Up,
776 typename = _Require<
777 __or_<is_same<_Up, pointer>,
778 __and_<is_same<pointer, element_type*>,
779 is_pointer<_Up>,
780 is_convertible<
781 typename remove_pointer<_Up>::type(*)[],
782 element_type(*)[]
783 >
784 >
785 >
786 >>
787 _GLIBCXX23_CONSTEXPR
788 void
789 reset(_Up __p) noexcept
790 { _M_t.reset(std::move(__p)); }
791
792 _GLIBCXX23_CONSTEXPR
793 void reset(nullptr_t = nullptr) noexcept
794 { reset(pointer()); }
795
796 /// Exchange the pointer and deleter with another object.
797 _GLIBCXX23_CONSTEXPR
798 void
799 swap(unique_ptr& __u) noexcept
800 {
801 static_assert(__is_swappable<_Dp>::value, "deleter must be swappable");
802 _M_t.swap(__u._M_t);
803 }
804
805 // Disable copy from lvalue.
806 unique_ptr(const unique_ptr&) = delete;
807 unique_ptr& operator=(const unique_ptr&) = delete;
808
809 private:
810#ifdef __glibcxx_out_ptr
811 template<typename, typename, typename...> friend class out_ptr_t;
812 template<typename, typename, typename...> friend class inout_ptr_t;
813#endif
814 };
815
816 /// @{
817 /// @relates unique_ptr
818
819 /// Swap overload for unique_ptr
820 template<typename _Tp, typename _Dp>
821 inline
822#if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
823 // Constrained free swap overload, see p0185r1
824 _GLIBCXX23_CONSTEXPR
825 typename enable_if<__is_swappable<_Dp>::value>::type
826#else
827 void
828#endif
829 swap(unique_ptr<_Tp, _Dp>& __x,
830 unique_ptr<_Tp, _Dp>& __y) noexcept
831 { __x.swap(__y); }
832
833#if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
834 template<typename _Tp, typename _Dp>
835 typename enable_if<!__is_swappable<_Dp>::value>::type
836 swap(unique_ptr<_Tp, _Dp>&,
837 unique_ptr<_Tp, _Dp>&) = delete;
838#endif
839
840 /// Equality operator for unique_ptr objects, compares the owned pointers
841 template<typename _Tp, typename _Dp,
842 typename _Up, typename _Ep>
843 _GLIBCXX_NODISCARD _GLIBCXX23_CONSTEXPR
844 inline bool
845 operator==(const unique_ptr<_Tp, _Dp>& __x,
846 const unique_ptr<_Up, _Ep>& __y)
847 { return __x.get() == __y.get(); }
848
849 /// unique_ptr comparison with nullptr
850 template<typename _Tp, typename _Dp>
851 _GLIBCXX_NODISCARD _GLIBCXX23_CONSTEXPR
852 inline bool
853 operator==(const unique_ptr<_Tp, _Dp>& __x, nullptr_t) noexcept
854 { return !__x; }
855
856#ifndef __cpp_lib_three_way_comparison
857 /// unique_ptr comparison with nullptr
858 template<typename _Tp, typename _Dp>
859 _GLIBCXX_NODISCARD
860 inline bool
861 operator==(nullptr_t, const unique_ptr<_Tp, _Dp>& __x) noexcept
862 { return !__x; }
863
864 /// Inequality operator for unique_ptr objects, compares the owned pointers
865 template<typename _Tp, typename _Dp,
866 typename _Up, typename _Ep>
867 _GLIBCXX_NODISCARD
868 inline bool
869 operator!=(const unique_ptr<_Tp, _Dp>& __x,
870 const unique_ptr<_Up, _Ep>& __y)
871 { return __x.get() != __y.get(); }
872
873 /// unique_ptr comparison with nullptr
874 template<typename _Tp, typename _Dp>
875 _GLIBCXX_NODISCARD
876 inline bool
877 operator!=(const unique_ptr<_Tp, _Dp>& __x, nullptr_t) noexcept
878 { return (bool)__x; }
879
880 /// unique_ptr comparison with nullptr
881 template<typename _Tp, typename _Dp>
882 _GLIBCXX_NODISCARD
883 inline bool
884 operator!=(nullptr_t, const unique_ptr<_Tp, _Dp>& __x) noexcept
885 { return (bool)__x; }
886#endif // three way comparison
887
888 /// Relational operator for unique_ptr objects, compares the owned pointers
889 template<typename _Tp, typename _Dp,
890 typename _Up, typename _Ep>
891 _GLIBCXX_NODISCARD _GLIBCXX23_CONSTEXPR
892 inline bool
893 operator<(const unique_ptr<_Tp, _Dp>& __x,
894 const unique_ptr<_Up, _Ep>& __y)
895 {
896 typedef typename
897 std::common_type<typename unique_ptr<_Tp, _Dp>::pointer,
898 typename unique_ptr<_Up, _Ep>::pointer>::type _CT;
899 return std::less<_CT>()(__x.get(), __y.get());
900 }
901
902 /// unique_ptr comparison with nullptr
903 template<typename _Tp, typename _Dp>
904 _GLIBCXX_NODISCARD _GLIBCXX23_CONSTEXPR
905 inline bool
906 operator<(const unique_ptr<_Tp, _Dp>& __x, nullptr_t)
907 {
908 return std::less<typename unique_ptr<_Tp, _Dp>::pointer>()(__x.get(),
909 nullptr);
910 }
911
912 /// unique_ptr comparison with nullptr
913 template<typename _Tp, typename _Dp>
914 _GLIBCXX_NODISCARD _GLIBCXX23_CONSTEXPR
915 inline bool
916 operator<(nullptr_t, const unique_ptr<_Tp, _Dp>& __x)
917 {
918 return std::less<typename unique_ptr<_Tp, _Dp>::pointer>()(nullptr,
919 __x.get());
920 }
921
922 /// Relational operator for unique_ptr objects, compares the owned pointers
923 template<typename _Tp, typename _Dp,
924 typename _Up, typename _Ep>
925 _GLIBCXX_NODISCARD _GLIBCXX23_CONSTEXPR
926 inline bool
927 operator<=(const unique_ptr<_Tp, _Dp>& __x,
928 const unique_ptr<_Up, _Ep>& __y)
929 { return !(__y < __x); }
930
931 /// unique_ptr comparison with nullptr
932 template<typename _Tp, typename _Dp>
933 _GLIBCXX_NODISCARD _GLIBCXX23_CONSTEXPR
934 inline bool
935 operator<=(const unique_ptr<_Tp, _Dp>& __x, nullptr_t)
936 { return !(nullptr < __x); }
937
938 /// unique_ptr comparison with nullptr
939 template<typename _Tp, typename _Dp>
940 _GLIBCXX_NODISCARD _GLIBCXX23_CONSTEXPR
941 inline bool
942 operator<=(nullptr_t, const unique_ptr<_Tp, _Dp>& __x)
943 { return !(__x < nullptr); }
944
945 /// Relational operator for unique_ptr objects, compares the owned pointers
946 template<typename _Tp, typename _Dp,
947 typename _Up, typename _Ep>
948 _GLIBCXX_NODISCARD _GLIBCXX23_CONSTEXPR
949 inline bool
950 operator>(const unique_ptr<_Tp, _Dp>& __x,
951 const unique_ptr<_Up, _Ep>& __y)
952 { return (__y < __x); }
953
954 /// unique_ptr comparison with nullptr
955 template<typename _Tp, typename _Dp>
956 _GLIBCXX_NODISCARD _GLIBCXX23_CONSTEXPR
957 inline bool
958 operator>(const unique_ptr<_Tp, _Dp>& __x, nullptr_t)
959 {
960 return std::less<typename unique_ptr<_Tp, _Dp>::pointer>()(nullptr,
961 __x.get());
962 }
963
964 /// unique_ptr comparison with nullptr
965 template<typename _Tp, typename _Dp>
966 _GLIBCXX_NODISCARD _GLIBCXX23_CONSTEXPR
967 inline bool
968 operator>(nullptr_t, const unique_ptr<_Tp, _Dp>& __x)
969 {
970 return std::less<typename unique_ptr<_Tp, _Dp>::pointer>()(__x.get(),
971 nullptr);
972 }
973
974 /// Relational operator for unique_ptr objects, compares the owned pointers
975 template<typename _Tp, typename _Dp,
976 typename _Up, typename _Ep>
977 _GLIBCXX_NODISCARD _GLIBCXX23_CONSTEXPR
978 inline bool
979 operator>=(const unique_ptr<_Tp, _Dp>& __x,
980 const unique_ptr<_Up, _Ep>& __y)
981 { return !(__x < __y); }
982
983 /// unique_ptr comparison with nullptr
984 template<typename _Tp, typename _Dp>
985 _GLIBCXX_NODISCARD _GLIBCXX23_CONSTEXPR
986 inline bool
987 operator>=(const unique_ptr<_Tp, _Dp>& __x, nullptr_t)
988 { return !(__x < nullptr); }
989
990 /// unique_ptr comparison with nullptr
991 template<typename _Tp, typename _Dp>
992 _GLIBCXX_NODISCARD inline bool
993 operator>=(nullptr_t, const unique_ptr<_Tp, _Dp>& __x)
994 { return !(nullptr < __x); }
995
996#ifdef __cpp_lib_three_way_comparison
997 template<typename _Tp, typename _Dp, typename _Up, typename _Ep>
998 requires three_way_comparable_with<typename unique_ptr<_Tp, _Dp>::pointer,
999 typename unique_ptr<_Up, _Ep>::pointer>
1000 _GLIBCXX23_CONSTEXPR
1001 inline
1002 compare_three_way_result_t<typename unique_ptr<_Tp, _Dp>::pointer,
1003 typename unique_ptr<_Up, _Ep>::pointer>
1004 operator<=>(const unique_ptr<_Tp, _Dp>& __x,
1005 const unique_ptr<_Up, _Ep>& __y)
1006 { return compare_three_way()(__x.get(), __y.get()); }
1007
1008 template<typename _Tp, typename _Dp>
1009 requires three_way_comparable<typename unique_ptr<_Tp, _Dp>::pointer>
1010 _GLIBCXX23_CONSTEXPR
1011 inline
1012 compare_three_way_result_t<typename unique_ptr<_Tp, _Dp>::pointer>
1013 operator<=>(const unique_ptr<_Tp, _Dp>& __x, nullptr_t)
1014 {
1015 using pointer = typename unique_ptr<_Tp, _Dp>::pointer;
1016 return compare_three_way()(__x.get(), static_cast<pointer>(nullptr));
1017 }
1018#endif
1019 /// @} relates unique_ptr
1020
1021 /// @cond undocumented
1022 template<typename _Up, typename _Ptr = typename _Up::pointer>
1023 struct __uniq_ptr_hash
1024 : public __hash_base<size_t, _Up>
1025#if ! _GLIBCXX_INLINE_VERSION
1026 , private __hash_empty_base<_Ptr>
1027#endif
1028 {
1029 size_t
1030 operator()(const _Up& __u) const
1031 noexcept(noexcept(std::declval<hash<_Ptr>>()(std::declval<_Ptr>())))
1032 { return hash<_Ptr>()(__u.get()); }
1033 };
1034
1035 template<typename _Up>
1036 using __uniq_ptr_hash_base
1037 = __conditional_t<__is_hash_enabled_for<typename _Up::pointer>,
1038 __uniq_ptr_hash<_Up>,
1039 __hash_not_enabled<typename _Up::pointer>>;
1040 /// @endcond
1041
1042 /// std::hash specialization for unique_ptr.
1043 template<typename _Tp, typename _Dp>
1044 struct hash<unique_ptr<_Tp, _Dp>>
1045 : public __uniq_ptr_hash_base<unique_ptr<_Tp, _Dp>>
1046 { };
1047
1048#ifdef __glibcxx_make_unique // C++ >= 14 && HOSTED
1049 /// @cond undocumented
1050namespace __detail
1051{
1052 template<typename _Tp>
1053 struct _MakeUniq
1054 { typedef unique_ptr<_Tp> __single_object; };
1055
1056 template<typename _Tp>
1057 struct _MakeUniq<_Tp[]>
1058 { typedef unique_ptr<_Tp[]> __array; };
1059
1060 template<typename _Tp, size_t _Bound>
1061 struct _MakeUniq<_Tp[_Bound]>
1062 { struct __invalid_type { }; };
1063
1064 template<typename _Tp>
1065 using __unique_ptr_t = typename _MakeUniq<_Tp>::__single_object;
1066 template<typename _Tp>
1067 using __unique_ptr_array_t = typename _MakeUniq<_Tp>::__array;
1068 template<typename _Tp>
1069 using __invalid_make_unique_t = typename _MakeUniq<_Tp>::__invalid_type;
1070}
1071 /// @endcond
1072
1073 /** Create an object owned by a `unique_ptr`.
1074 * @tparam _Tp A non-array object type.
1075 * @param __args Constructor arguments for the new object.
1076 * @returns A `unique_ptr<_Tp>` that owns the new object.
1077 * @since C++14
1078 * @relates unique_ptr
1079 */
1080 template<typename _Tp, typename... _Args>
1081 _GLIBCXX23_CONSTEXPR
1082 inline __detail::__unique_ptr_t<_Tp>
1083 make_unique(_Args&&... __args)
1084 { return unique_ptr<_Tp>(new _Tp(std::forward<_Args>(__args)...)); }
1085
1086 /** Create an array owned by a `unique_ptr`.
1087 * @tparam _Tp An array type of unknown bound, such as `U[]`.
1088 * @param __num The number of elements of type `U` in the new array.
1089 * @returns A `unique_ptr<U[]>` that owns the new array.
1090 * @since C++14
1091 * @relates unique_ptr
1092 *
1093 * The array elements are value-initialized.
1094 */
1095 template<typename _Tp>
1096 _GLIBCXX23_CONSTEXPR
1097 inline __detail::__unique_ptr_array_t<_Tp>
1098 make_unique(size_t __num)
1099 { return unique_ptr<_Tp>(new remove_extent_t<_Tp>[__num]()); }
1100
1101 /** Disable std::make_unique for arrays of known bound.
1102 * @tparam _Tp An array type of known bound, such as `U[N]`.
1103 * @since C++14
1104 * @relates unique_ptr
1105 */
1106 template<typename _Tp, typename... _Args>
1107 __detail::__invalid_make_unique_t<_Tp>
1108 make_unique(_Args&&...) = delete;
1109
1110#if __cplusplus > 201703L
1111 /** Create a default-initialied object owned by a `unique_ptr`.
1112 * @tparam _Tp A non-array object type.
1113 * @returns A `unique_ptr<_Tp>` that owns the new object.
1114 * @since C++20
1115 * @relates unique_ptr
1116 */
1117 template<typename _Tp>
1118 _GLIBCXX23_CONSTEXPR
1119 inline __detail::__unique_ptr_t<_Tp>
1120 make_unique_for_overwrite()
1121 { return unique_ptr<_Tp>(new _Tp); }
1122
1123 /** Create a default-initialized array owned by a `unique_ptr`.
1124 * @tparam _Tp An array type of unknown bound, such as `U[]`.
1125 * @param __num The number of elements of type `U` in the new array.
1126 * @returns A `unique_ptr<U[]>` that owns the new array.
1127 * @since C++20
1128 * @relates unique_ptr
1129 */
1130 template<typename _Tp>
1131 _GLIBCXX23_CONSTEXPR
1132 inline __detail::__unique_ptr_array_t<_Tp>
1133 make_unique_for_overwrite(size_t __num)
1134 { return unique_ptr<_Tp>(new remove_extent_t<_Tp>[__num]); }
1135
1136 /** Disable std::make_unique_for_overwrite for arrays of known bound.
1137 * @tparam _Tp An array type of known bound, such as `U[N]`.
1138 * @since C++20
1139 * @relates unique_ptr
1140 */
1141 template<typename _Tp, typename... _Args>
1142 __detail::__invalid_make_unique_t<_Tp>
1143 make_unique_for_overwrite(_Args&&...) = delete;
1144#endif // C++20
1145
1146#endif // C++14 && HOSTED
1147
1148#if __cplusplus > 201703L && __cpp_concepts && _GLIBCXX_HOSTED
1149 // _GLIBCXX_RESOLVE_LIB_DEFECTS
1150 // 2948. unique_ptr does not define operator<< for stream output
1151 /// Stream output operator for unique_ptr
1152 /// @relates unique_ptr
1153 /// @since C++20
1154 template<typename _CharT, typename _Traits, typename _Tp, typename _Dp>
1155 inline basic_ostream<_CharT, _Traits>&
1156 operator<<(basic_ostream<_CharT, _Traits>& __os,
1157 const unique_ptr<_Tp, _Dp>& __p)
1158 requires requires { __os << __p.get(); }
1159 {
1160 __os << __p.get();
1161 return __os;
1162 }
1163#endif // C++20 && HOSTED
1164
1165#if __cpp_variable_templates
1166 template<typename _Tp>
1167 constexpr bool __is_unique_ptr = false;
1168 template<typename _Tp, typename _Del>
1169 constexpr bool __is_unique_ptr<unique_ptr<_Tp, _Del>> = true;
1170#endif
1171
1172 /// @} group pointer_abstractions
1173
1174#if __cplusplus >= 201703L
1175 namespace __detail::__variant
1176 {
1177 template<typename> struct _Never_valueless_alt; // see <variant>
1178
1179 // Provide the strong exception-safety guarantee when emplacing a
1180 // unique_ptr into a variant.
1181 template<typename _Tp, typename _Del>
1182 struct _Never_valueless_alt<std::unique_ptr<_Tp, _Del>>
1183 : std::true_type
1184 { };
1185 } // namespace __detail::__variant
1186#endif // C++17
1187
1188_GLIBCXX_END_NAMESPACE_VERSION
1189} // namespace
1190
1191#endif /* _UNIQUE_PTR_H */
1192